From: Andrew Morton <akpm@linux-foundation.org>
To: "Bang Li" <libang.li@antgroup.com>
Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org,
" 朱辉(茶水) " <teawater@antgroup.com>,
"Yan Yan(cailing)" <yanyan.yan@antgroup.com>
Subject: Re: [PATCH] mm/compaction: Reduce unnecessary loops
Date: Fri, 12 Jan 2024 11:25:51 -0800 [thread overview]
Message-ID: <20240112112551.bbc9d5114fd2c6fb421fed2d@linux-foundation.org> (raw)
In-Reply-To: <20240112073524.80724-1-libang.li@antgroup.com>
On Fri, 12 Jan 2024 15:35:24 +0800 "Bang Li" <libang.li@antgroup.com> wrote:
> Compaction will be triggered when we write 1 to '/proc/sys/vm/
> compact_memory'. During the execution of the process, when we send
> SIGKILL to terminate the compaction, the process does not exit
> immediately. Instead, it will continue to loop through the remaining
> zones and nodes before exiting.
>
> in my environment:
>
> [root]# cat /proc/buddyinfo
> Node 0, zone DMA 1 1 1 0 2 1 1 0 1 1 3
> Node 0, zone DMA32 1666 1123 804 625 488 356 321 278 209 178 250
> Node 0, zone Normal 58852 83160 49983 9812 2287 1229 19604 24471 10346 5219 12205
> [root]# echo 1 > /sys/kernel/debug/tracing/events/compaction/mm_compaction_end/enable
>
> before the patch:
>
> [root]# timeout --signal=SIGKILL 0.002 bash -c 'echo 1 > /proc/sys/vm/compact_memory'
> [root]# cat /sys/kernel/debug/tracing/trace_pipe
> <...>-26494 [014] ..... 226.468993: mm_compaction_end: zone_start=0x1 migrate_pfn=0xe00 free_pfn=0xe00 zone_end=0x1000, mode=sync status=complete
> <...>-26494 [014] ..... 226.469718: mm_compaction_end: zone_start=0x1000 migrate_pfn=0x20a80 free_pfn=0xffe00 zone_end=0x100000, mode=sync status=contended
> <...>-26494 [014] ..... 226.469720: mm_compaction_end: zone_start=0x100000 migrate_pfn=0x100000 free_pfn=0x307fe00 zone_end=0x3080000, mode=sync status=contended
>
> after the patch:
>
> [root]# timeout --signal=SIGKILL 0.002 bash -c 'echo 1 > /proc/sys/vm/compact_memory'
> [root]# cat /sys/kernel/debug/tracing/trace_pipe
> <...>-17491 [053] ..... 109.005387: mm_compaction_end: zone_start=0x1 migrate_pfn=0xe00 free_pfn=0xe00 zone_end=0x1000, mode=sync status=complete
> <...>-17491 [053] ..... 109.006139: mm_compaction_end: zone_start=0x1000 migrate_pfn=0x22220 free_pfn=0xffe00 zone_end=0x100000, mode=sync status=contended
>
> Although it exits quickly after receiving the SIGKILL signal, a better
> solution is to terminate the loop early after receiving the SIGKILL
> signal.
>
What is the use case here? The requirement? Why is this change
valuable to anyone?
next prev parent reply other threads:[~2024-01-12 19:26 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-01-12 7:35 [PATCH] mm/compaction: Reduce unnecessary loops Bang Li
2024-01-12 19:25 ` Andrew Morton [this message]
2024-01-13 5:52 ` Bang Li
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